A 3D visual effect may be created by a 3D projector system by operating the projector to deliver left and right images representing different viewpoints to a viewer who is wearing special 3D viewing eyeglasses. For example, the viewer may wear polarized eyeglasses having polarizing filters (e.g. linearly polarized glasses or circularly polarized eyeglasses). In such case the left and right images are each polarized so that they can be seen by the intended eye but not the other eye when wearing the polarized eyeglasses. In other display technologies, the user may wear spectral filtration eyeglasses to view different left and right images. In such case the projector is operated to provide spectrally filtered light to the viewer so that the left eye is presented with light in a first set of spectral bands (providing a left image) and the right eye is presented with light in a complementary, second set of spectral bands (providing a right image). In each case the viewer's brain combines and interprets the left and right images to perceive a single 3D image having the illusion of depth.
A problem with the above-described 3D viewing technologies is that the 3D image viewed using eyeglasses may be prone to flickering and/or image distortion (e.g. the image intensity and coloring may be “off”). Another problem is that the eyeglasses may reduce the image brightness and may be cumbersome to wear. These problems may cause viewer eyestrain and discomfort. There is a general desire for projector systems which can provide an eyeglasses-free 3D viewing experience.
A further problem with the above-described 3D viewing technologies is the lack of a motion parallax depth cue. The effect of motion parallax is that as a viewer moves, closer objects are perceived to shift relatively further than do distant objects. Motion parallax can be simulated by presenting different perspectives of a scene to the viewer as he or she moves from place to place. There is a general desire for projector systems which can produce motion parallax depth cues for a more realistic and enjoyable 3D viewing experience.
Multiview projector systems exist which can be operated to provide different viewpoints (views) to each viewing position. Typically these projector systems illuminate a reflective screen having an optical layer or filter (e.g. having a rippled surface) which reflects the image from the projector toward different viewing positions.
For example, FIG. 1 shows a front-view projector system 9. Front-view projector system 9 includes a projector 12 and a reflective screen 14. Light is projected from projector 12 to screen 14. Screen 14 then reflects the light toward a viewing area in front of the screen. In the illustrated example, two viewers 11A, 11B are shown respectively positioned at viewpoint locations V1, V2. To produce images at multiple viewing locations, such as images at viewpoint locations V1, V2 as shown in FIG. 1, screen 14 may include an optical layer or filter to reflect light to such viewing locations.
A disadvantage of a projector system such as that shown in FIG. 1 is that the spatial resolution of the image at each viewpoint is reduced from the projector resolution by the number of viewpoints. This may result in degradation of image quality. For example, the total resolution of the FIG. 1 projector system may be related to the number of viewpoints and spatial resolution as follows:R=N·VR  Equation [1]
where R is the resolution of the projector (e.g. 1920×1080), N is the number of viewpoints (e.g. 48), and VR is the resulting resolution at each viewpoint (e.g. 40×1080). In this example, viewpoints are multiplexed horizontally. In other cases, viewpoints may be multiplexed vertically, or both horizontally and vertically. For the above example, with 48 viewpoints being displayed, the resolution of the image at each viewpoint (i.e. 40×1080) would be generally too low for producing a good quality image.
Patent literature describing technology in the general field of this invention includes:
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There is a general desire for a multiview projector system which can accomplish one or more of the following objectives:
produce images at a higher spatial resolution at each viewpoint than conventional multiview projector systems;
adapt the image displayed at each viewpoint for different viewing circumstances; and
optimize or adjust aspects of image quality at each viewpoint.
The foregoing examples of the related art and limitations related thereto are intended to be illustrative and not exclusive. Other limitations of the related art will become apparent to those of skill in the art upon a reading of the specification and a study of the drawings.